In recent times, with a smart phone or a PDA equipped with a touch screen, characters are input by directly touching a screen with a finger instead of using physical buttons. In particular, various techniques for sensing single or multiple finger touches and sensing a sliding of a finger have been gradually commercialized. Further, as various input interfaces are available, various methods for inputting characters have been suggested.
However, conventionally, when a user touches a small virtual button displayed on a small touch screen of a smart phone with his/her finger, the user often makes typographical errors. That is, most smart phones have 24 or more small virtual buttons arranged and displayed similarly to a keyboard layout called “QWERTY” used in a typical desktop PC. As for a capacitive screen equipped in a smart phone, characters are usually input by using a finger instead a touch pen, and, thus, it is somewhat inconvenient to input characters.
When a user selects a virtual button displayed on a touch screen, the virtual button is hidden by a finger of the user. That is, a character button is hidden from user's view by his/her finger, and, thus, immediacy of use can be decreased.
Therefore, it is necessary to improve a conventional character input method in which two-dimensional planar buttons are simply displayed in a virtual space.